Periodic solutions for the Lorentz force equation with singular potentials

We provide sufficient conditions for the existence of periodic solutions of the Lorentz force equation, which models the motion of a charged particle under the action of an electromagnetic fields. The basic assumptions cover relevant models with singularities like Coulomb-like electric potentials or the magnetic dipole.     

Effect of viscosity on the fission dynamics of the excited compound nucleus 251Es produced in fusion reaction

A stochastic approach based on two-dimensional dynamical model has been used to simulate the fission dynamics of the excited compound nucleus ²⁵¹Es produced in ¹⁹F+²³²Th reaction. In the dynamical calculations the elongation parameter has been used as the first dimension and the projection of the total spin of the compound nucleus onto the symmetry axis, K, considered as the second dimension. The value of post-saddle friction was inferred by reproducing experimental data on the mean pre-scission neutron multiplicity for ²⁵¹Es. It was shown that the results of calculations are in good agreement with the experimental data by applying values of the post-saddle friction equal to 13−15×10²¹s⁻¹.     

叶绿素a锰（Ⅲ）和叶绿素a锰（Ⅱ）的合成和光谱

叶绿素ａ锰（Ⅲ）（Ｍｎ（Ⅲ）－Ｃｈｌ－ａ）由脱镁叶绿素（Ｐｈｅｏ－ａ）和醋酸锰（Ⅱ）合成而得，用反相高效液相色谱法分离纯化，叶绿素ａ锰（Ⅱ）（Ｍｎ（Ⅱ）－Ｃｈｌ－ａ）用Ｎａ２Ｓ２Ｏ４还原时绿素ａ锰（Ⅲ）获得，研究了它们的元素分析（ＥＡ），紫外可见吸附光谱（ＵＶ－Ｖｉｓ）和傅里叶红外吸收光谱（ＦＴ－ＩＲ）证明了此二种配合物的合成，并给出了（Ｍｎ（Ⅲ）－Ｃｈｌ－ａ）与（Ｍｎ（Ⅱ）－Ｃｈｌ－ａ）的组成分     

Natural widths and Coster–Kronig transitions of L X-ray spectra in elements between Pd and Sb

The Lα and Lβ X-ray emission spectra in the elements between Pd (Z=46) and Sb (Z=51) were measured using a high-resolution double-crystal vacuum spectrometer. The relative intensities of satellite structures, which originate in L₁L₃M_4,5 Coster–Kronig transitions, were estimated to that of each diagram line, and compared with calculated values. According to the work of Chen et al. [1977a. Theoretical L-shell Coster–Kronig energies 11⩽Z⩽103. At. Data Nucl. Data Tables 19, 97–151], Salgueiro et al. [1987. J. Phys. (Paris) 48 Colloq. C9, 609] and Vlaicu et al. [1998. Investigation of the 74W L emission spectra and satellites. Phys. Rev. A 58, 3544] L₁L₃M₄ Coster–Kronig transition is forbidden for 50⩽Z⩽77, and L₁L₃M₅ Coster–Kronig transition is forbidden for 50⩽Z⩽73. The results suggest that L₁L₃M_4,5 Coster–Kronig transitions may be allowed even for Sn (Z=50) and Sb (Z=51).     

Simulation of boron nitride sputtering process and its comparisonwith experimental data

In the paper, TRIM and TRIDYN simulation codes were used to simulate the sputtering processes of boron nitride (BN) films during bombardment of ions. The TRIM and TRIDYN codes are applicable to the simulation of sputtering processes of different target materials with amorphous and polycrystalline structure. The results of the simulations are compared with experimental data. The sputtering experiments of polycrystalline hexagonal BN (h-BN) and cubic BN (c-BN) films were performed in a Commonwealth Scientific Corporation (CSC) 38-cm ion beam source device. The comparison of calculated and experimental results indicated that a) the experimental sputtering yields of h-BN and c-BN films bombarded with Ar⁺ ions versus the angle of incidence are in reasonable agreement with the calculated results; b) the sputtering yields of h-BN and c-BN bombarded with Ar⁺ are nearly of the same values versus the angle of incidence-preferential sputtering of h-BN was not found; c) the calculated sputtering. Yields of BN as a function of Ar⁺ ion energy are very sensitive to values of the surface binding energy (SEE); and d) surface binding energy between 2 and 3 eV for BN appears to be reasonable for the simulation of sputtering process of h-BN and c-BN films     

Electrochemical impedance spectroscopic study of the rate-determining step of Li ion intercalation and deintercalation in LixNiO2 cathodes

The rate-determining step of the intercalation and deintercalation process of lithium ions in Li_xNiO₂ cathodes was studied by electrochemical impedance spectroscopic (EIS) analysis. EISs of the electrode process are composed of two semicircles. The higher frequency semicircle is related to the charge transfer resistance (R_ct) and the double layer capacitance (C_dl), while the lower frequency semicircle results from ion incorporation impedance (R_lattice) and space charge capacitance (C_sc). The assignment of the latter capacitance is discussed. It is found that R_lattice is 1000 times larger than R_ct. Accordingly, in most cases the ion incorporation into the lattice dominates the kinetic behavior. But for the ideal hexagonal phase, in the deintercalated state the Warburg impedance becomes important. As a result, the ion diffusion in the lattice is the rate-determining step. Paper presented at the 3rd Euroconference on Solid State Ionics, Teulada, Sardinia, Italy, Sept. 15–22, 1996     

关于(0,1)的对称和规范矩阵

给出更多的对于给定行和向量存在（０，１）对称矩阵的等价条件，同时也讨论了（０，１）规范矩阵的情形．     

Tunable diode laser spectroscopy of copper,cadmium, and indium at 325 nm

A tunable frequency-doubled external-cavity diode laser has been recently developed for atomic absorption spectroscopy in the wavelength range from 320 to 327 nm. The line width of the laser is 0.003 pm. In this work the light source has been applied to the laser absorption spectroscopy of copper at 324.754 nm, cadmium at 326.106 nm, and indium at 325.609 nm and 325.856 nm. The Cu transition was measured in three different environments: in a direct current plasma, a diffusion flame, and in a low-pressure hollow-cathode discharge. Both the plasma and the flame were at atmospheric pressure. The Cd and In transitions were measured in the diffusion flame. A Voigt profile was fit to the measured spectra taking into account the hyperfine structure. From the measured absorption lines spectral reference data for Cu is extracted.     

稀土(III)-冠醚配位反应的热力学性质: II. 镧系(III)高氯酸 盐与二苯并18- 冠-6在无水乙腈中配位反应的量热滴定研究

用滴定量热计于298.15K测定了除钷、镥以外的全部十三种镧系(III)高氯酸盐与二苯并-18-冠-6在无水乙腈中的配位作用。借助计算机用自编程序算出了配位反应的生成常数和焓变,进而算出了配位反应的自由能变化和熵变化。探讨了镧系(III)阳离子对配位反应的影响。此外,还比较了几种不同冠醚与高氯酸镧在无水乙腈中配位反应的热力学性质。